A fire swept through a Honduran prison killing more than 300 inmates, officials said on Wednesday, warning the toll may rise with many inmates burned to death in their cells by the inferno.

Survivors described wrenching scenes as inmates were engulfed by choking smoke and flames, some unable to flee because they were still shackled to the bars of their cells in what is the world's worst prison blaze in a decade.

Those who were able "tried to save themselves by hurling themselves into the shower, sinks" and any other source of water they could find, one survivor said after the blaze in the jail in the central city of Comayagua.

Some of the inmates escaped by jumping from the prison rooftop, and there were reports that some had fled the crowded facility and were on the loose.

Honduran officials said that of the more than 850 inmates housed in the prison, hundreds were still unaccounted for, although they noted some might have escaped during the fire. Those who died were killed mostly by smoke inhalation.

The inferno broke out at around 10:50 pm Tuesday (0450 GMT Wednesday), and took about three hours to bring under control.

Officials were unclear about the cause, at first believing that the blaze was sparked by a short circuit. But later they did not rule out that the fire might have been deliberately set by inmates.

Victor Sevilla said he was haunted by the desperate pleas for help from his fellow prisoners trapped in their cells and who could not get out in time.

"I woke up with all the screaming from my fellow inmates, who were already breaking the wood and zinc ceiling," Sevilla, 23, told AFP, speaking at Comayagua's Santa Teresa hospital where he was being treated for a broken ankle after jumping to safety from a wall.

Fabricio Contreras, 34, said he was also woken up by the commotion. The prisoners headed to the main gate, "but nobody opened it," he said.

"The prison guards were firing in the air because they thought it was a breakout," he said.

Prison officials and rescue workers Wednesday dressed in white hazard suits moved in Wednesday to remove the charred remains, as distraught relatives wept openly, clinging to each other as they mourned the deaths of their loved ones.

Many blamed prison authorities for moving too slowly to save them. "My son died of asphyxiation there," said Leonidas Medina, 69, at a local hospital.

"The guards wouldn't open the door and they (the inmates) burned to death," he said. "They wouldn't have died if they had just opened the doors."

The enormity of the disaster led President Porfirio Lobo to suspend Honduras's top penal officials, as well as those at the Comayagua penitentiary while an investigation is underway.

The Organization of American States (OAS) in Washington said it was also launching a probe into the disaster.

Prisons in Honduras -- as is the case throughout Latin America -- are notoriously overcrowded. The country's 24 penal facilities officially have room for 8,000 inmates, but actually house 13,000.

The prison in Comayagua, located some 90 kilometers (56 miles) north of the capital city of Tegucigalpa, held almost double its official inmate capacity.

The facility is also just 500 meters (1,650 feet) from a highway that links San Pedro Sula, the economic center of Honduras, with the capital city Tegucigalpa.

The governor of the region Paola Castro said her office received a phone call from someone claiming to be an inmate, telling her that another prisoner had set the fire in a suicide bid.

Desperate relatives, frustrated at being left in the dark about the fate of their loved ones, clashed with police and then stormed the prison gates early Wednesday.

Security forces fired into the air in a bid to stop the unrest, but the relatives burst through a locked gate and flooded into the facility, where they gathered in a front courtyard.

"My brother Roberto Mejia was in unit six," an emotional Glenda Mejia told AFP. "They've told me that the inmates from that unit are all dead."

Officials here expressed sympathy with the relatives' frustration, but called for patience.

"We understand the pain of the families, but we have to follow a process under the law," Security Minister Pompeyo Bonilla said. "We call for calm. It is a very difficult situation."